Polyacetal carboxylates have been demonstrated to be useful as builders in detergent formulations. Crutchfield U.S. Pat. No. 4,144,226 describes the preparation of polyacetal carboxylates by polymerization of an ester of glyoxylic acid, preferably methyl glyoxylate. The glyoxylic acid ester monomer may be prepared by vapor phase oxidation of the corresponding ester of glycolic acid. This process can be represented as follows: ##STR1##
Various catalysts have been proposed for use in this vapor phase process including silver as well as a catalyst composed of one or more of vanadium, molybdenum, silver, and copper in combination with a promoter such as tin, antimony, bismuth, or an element of Group IA or Group IIA of the Periodic Table. See U.S. Pat. No. 4,340,748. While the selectivity and conversion obtained with silver catalysts are good, an improvement in the level of conversion, and especially conversion and selectivity, is desirable.